C-nitroso compounds and use thereof

ABSTRACT

A C-nitroso compound having a molecular weight ranging from about 225 to about 1,000 (from about 225 to about 600 for oral administration) on a monomeric basis wherein a nitroso group is attached to a tertiary carbon, which is obtained by nitrosylation of a carbon acid having a pKa less than about 25, is useful as an NO donor. When the compound is obtained from a carbon acid with a pKa less than about 10, it provides vascular relaxing effect when used at micromolar concentrations and this activity is potentiated by glutathione to be obtained at nanomolar concentrations. When the compound is obtained from a carbon acid with a pKa ranging from about 15 to about 20, vascular relaxing effect is obtained at nanomolar concentrations without glutathione. The compound is preferably water-soluble and preferably contains a carbon alpha to the nitrosylated carbon which is part of a ketone group. In one embodiment, the C-nitroso compound is obtained by nitrosylation of a conventional drug or such drug modified to modify the carbon acid pKa thereof When such drug is a nonsteroidal anti-inflammatory drug, the resulting C-nitroso compound functions as a COX-1 and COX-2 inhibitor without the deleterious effects associated with COX-1 inhibition but with the advantageous effects associated with COX-1 and COX-2 inhibition. One such C-nitroso compound is a nitrosoketoibuprofen. A specific example of this kind of compound is isolated as dimeric 2-[4′-(α-nitroso)isobutyrylphenyl]propionic acid. 
 
In another case, the C-nitroso compound contains the moiety  
                 
where X is S, O or NR. One embodiment is directed to COX-2 inhibitors where a tertiary carbon atom and/or an oxygen atom and/or a sulfur atom is nitrosylated.

TECHNICAL FIELD

The invention relates to C-nitroso compounds which are therapeuticallyactive at low concentrations as NO donors.

BACKGROUND OF THE INVENTION

NO donors are known to be useful for therapeutic utility, e.g., toprevent restenosis following angioplasty (Groves, P., et al.,Cardiovascular Research 26, 615-619 (1992)), to inhibit platelets toprevent coagulation and thrombus formation (Groves, P., et al.,Circulation 87, 590-597 (1993)) and to treat angina (Knight, et al.,Circulation 95, 125-132 (1997)). NO donors are considered to haveadditional therapeutic utility in cancer, killing microbes and viruses,relaxing airways and intestinal smooth muscle (e.g., for treating asthmaand esophageal spasms), in promoting erectile function and in treatmentof heart failure and urinary incontinence.

NO donors are described in “methods in Nitric Oxide Research,” edited byFeelisch, M., and Stamler, J. S., John Wiley & Sons, New York, 1996 atpages 71-115. These NO donors are O-nitroso and S-nitroso compounds, andC-nitroso compounds that are excluded from the invention herein.

Twenty-two additional C-nitroso compounds are described in Rehse, K, etal., Arch. Pharm. Pharm. Med. Chem. 331, 104-110 (1998). These compoundsare of low molecular weight and are not water-soluble and were shown tobe weakly active. Other C-nitroso compounds are described in Rehse, K,et al., Arch. Pharm. Pharm. Med. Chem. 331, 79-84 (1998); these arenitro-nitroso compounds and the specific compounds mentioned areexcluded from the invention herein.

Other C-nitroso compounds which are old are3-methyl-3-nitroso-2,4-pentanedione and3-ethyl-3-nitroso-2,4-pentanedione. These compounds and their synthesisare described in Sklyar, Yu. E., et al., Khimiya GeterotsiklicheskikhSoedinenii 5, 70-73 (1969). These compounds are of low molecular weightand do not meet the definition of water solubility set forthhereinafter.

SUMMARY OF THE INVENTION

It has been discovered in a first embodiment herein that certainC-nitroso compounds of higher molecular weight than have previously beenprepared, especially those that are water-soluble, are therapeuticallyactive as NO donors at nanomolar concentrations, in some cases when usedalone and in some cases in the presence of glutathione.

The C-nitroso compounds of the first embodiment herein have a nitrosogroup attached to a tertiary carbon. Otherwise there is an essentiallyirreversible tautomerization to the corresponding oxime which isgenerally not active. It has been discovered herein that the nitrosogroup being attached to a tertiary carbon is important for goodactivity.

The C-nitroso compounds of the first embodiment herein have a molecularweight ranging from about 225 to about 1,000 on a monomeric basis. Thehigh activity obtained for compounds of this molecular weight isconsidered to be surprising and means that many drugs that are now beingused can be converted to C-nitroso compounds providing not only thetherapeutic effect of the starting drug but also advantages provided bynitroso group including relaxation effect and other advantages asdescribed later.

The C-nitroso compounds of the first embodiment herein are obtained bynitrosylation of a carbon acid having a pKa less than about 25.C-nitroso compounds derived from carbon acids with lower acidities(higher pKa values) will not act as useful donors of NO.

Thus, the invention of the first embodiment in its broad aspects isdirected to a C-nitroso compound having a molecular weight ranging fromabout 225 to about 1,000 on a monomer basis wherein a nitroso group isattached to a tertiary carbon, which is obtained by nitrosylation of acarbon acid having a pKa less than about 25.

The C-nitroso compound is preferably water-soluble and preferablycontains carbon alpha to nitrosylated carbon which is part of a ketonegroup.

In one subgenus, the C-nitroso compound is obtained by nitrosylation ofa carbon acid having a pKa less than 10. Compounds of this subgenus,when used alone, have NO donating and relaxation providing activity whenused at micromolar concentrations. However, it has been discoveredherein that this activity is potentiated by glutathione, so compounds ofthis subgenus, when administered with or to react with glutathione, aretherapeutically active (to provide NO donating and relaxation effects)when used at nanomolar concentrations. Thus, an embodiment herein isdirected to a method of treating a patient with such C-nitroso compoundat nanomolar (e.g., from 0.1 to 900 nanomolar) concentrations, togetherwith glutathione to provide NO donating and relaxing effect, where thepatient is one in need of NO donating and/or relaxing effect and/or isin need of nitrosoglutathione.

In another subgenus, the C-nitroso compound is obtained by nitrosylationof a carbon acid having a pKa ranging from about 15 to about 20. It hasbeen found in this case that the compound is therapeutically active andprovides nitrosylating activity and relaxing effect when used atnanomolar concentrations without potentiation and that glutathioneinhibits the activity of the compound.

It has been discovered herein that C-nitroso compounds of the inventionherein can be obtained by nitrosylating the tertiary carbon atom of aconventional drug if that drug constitutes a carbon acid having a pKaless than 25 or can be converted to a carbon acid having a pKa less than25 and will provide a C-nitroso compound meeting the aforedescribedmolecular weight limitations. The resulting C-nitroso compounds retainthe activity of the drug and additionally provide the relaxation effectassociated with NO and can provide other beneficial effect as describedbelow.

It has been discovered herein that when the conventional drug is anonsteroidal anti-inflammatory drug that is a COX-1 and a COX-2inhibitor, the resulting C-nitroso compound will function as a COX-1 andCOX-2 inhibitor without the deleterious effects associated with COX-1inhibition but with the advantages associated with COX-1 and COX-2inhibition. In particular, COX-1 mediates production of thromboxanewhich mediates platelet aggregation thereby providing a deleteriousdeletions effect; inhibition of COX-1 reverses this effect. Thisreversal is reinforced by the C-nitroso nonsteroidal anti-inflammatorydrugs herein. On the other hand, COX-1 inhibitors inhibit production ofprostaglandins which protect against ulcers; the NO associated with thenonsteroidal anti-inflammatory drugs herein protects against thisdeleterious side effect. While the COX-1 inhibiting effect that mediatesstomach attack is partly related to a deficiency of NO, there is an NObeneficial effect that may be COX-1 independent that more than negatesthe detrimental effect of inhibition of COX-1 production ofprostaglandins. Thus, the C-nitroso nonsteroidal anti-inflammatoryCOX-1/COX-2 inhibitors herein provide an advantage over selectiveinhibitors of COX-2 in also providing the advantageous effectsassociated with COX-1 inhibition and other NO beneficial effects.Furthermore, C-nitroso selective COX-2 inhibitors provide not only theadvantages of COX-2 inhibition but also some of the advantagesassociated with COX-1 inhibition. Furthermore, the NO in C-nitroso COXinhibitors potentiates the alleviating effect of COX inhibitors onurinary incontinence.

Dimeric 2-[4′-(α-nitroso)isobutyrylphenyl]propionic acid has beensynthesized herein and is obtained by C-nitrosylation of ibuprofenmodified to have a lower carbon acid pKa. It represents a C-nitrosocompound herein obtained by nitrosylation of a carbon acid having a pKaranging from about 15 to about 25 and is therapeutically active withoutglutathione when used at nanomolar concentrations.

Thus, one embodiment herein is directed to a method of treating apatient with an inflammatory or painful disorder comprisingadministering to said patient a therapeutically effective (inflammationand/or pain relieving) amount of a C-nitroso compound of the instantinvention which is obtained by nitrosylation of the tertiary carbon of aconventional nonsteroidal anti-inflammatory drug which has a carbon acidpKa ranging from about 15 to about 20 or such modified to have thiscarbon acid pKa where the C-nitroso compound preferably is dimeric2-[4′-(α-nitroso)isobutyrylphenyl]propionic acid or an aqueous solutionthereof

It has also discovered herein that the pKa of a carbon acid of acompound may be used to target an NO group to provide nitrosylatedcompound. This is not the case in preparing other classes of NO donor,e.g., —ONO and —SNO NO donors.

In addition, there has been discovered a new class of compounds, thatare C-nitroso compounds and contain the moiety

where X is S, O or NR and protonated derivatives thereof which areuseful in promoting compound lifetime and providing modulatedbioactivity. These compounds have a molecular weight ranging, forexample, from about 100 to about 1,000 on a monomeric basis. Thesecompounds are referred to as C-nitroso compounds of the secondembodiment herein. The compounds of Rehse, K et al., Arch. Pharm. Pharm.Med. Chem 331, 79-84 (1998) are excluded from the new class of compoundsherein.

Shinmura, K, et al., PNAS 97, 10197-10202 (2000) shows COX-2 mediatescardioprotective effects of ischemic preconditioning, in particular thelate phase of ischemic preconditioning (in this case the heart is madeischemic briefly to protect against a subsequent ischemia that is muchmore severe). Thus COX-2 inhibitors interfere with this cardioprotectiveeffect. However, in the case of C-nitroso COX-2 inhibitors herein the NOreplaces the COX-2 mediation that is lost so there is a special benefit.This is also a similar benefit obtained with O-nitroso and S-nitrosoCOX-2 inhibitors. Thus, one embodiment herein is directed to COX-2inhibitors where a tertiary carbon or an oxygen or sulfur isnitrosylated.

As used herein, the term “carbon acid” means compound that contains a CHgroup which disassociates to C⁻ and H⁺.

As used herein, the term “water-soluble” means dissolves in water atleast to provide a concentration of 1 micromolar.

As used herein, the term “conventional drug” means therapeutic agentwithout NO donor effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-10 are tracings of tension (force) versus time withconcentrations of compound also shown for particular times and showresults of Example II.

FIG. 1 is directed results with compound (129a) described hereinafter.

FIG. 2 is directed to results with C-nitroso-methylmalonic acid.

FIG. 3 is directed to result with C-nitrosobenzene.

FIG. 4 is directed to results with C-nitrosophenol.

FIG. 5 is directed to results with the C-nitrosoketoibuprofensynthesized in Example I.

FIG. 6 is similar to FIG. 5 but with indications of presence of dimerand more denotations of concentration.

FIG. 7 is directed to results for the combination of theC-nitrosoketoibuprofen and 100 μM glutathione.

FIG. 8 similar to FIG. 5 but with another concentration denoted.

FIG. 9 is directed to results for 3-methyl-3-nitroso-2,4-pentanedione,including potentiation with glutathione (GSH).

FIG. 10 is directed to results for 2-methyl-2-nitrosopropane.

FIGS. 2, 3, 4, 9 and 10 are directed to results with reference compoundsalthough FIG. 9 is relied on for showing the potentiation effect thatoccurs in one embodiment of the invention. FIGS. 1 and 5-8 are directedto results with C-nitroso compound of embodiments of the invention.

DETAILED DESCRIPTION

We turn now to the embodiment of the invention directed to a C-nitrosocompound having a molecular weight ranging from about 225 to about 1,000on a monomer basis wherein a nitroso group is attached to a tertiarycarbon which is obtained by nitrosylation of a carbon acid having a pKaless than about 25. The molecular weight typically ranges from about 225to about 600 on a monomer basis for oral administration.

We turn now to the subgenus where the C-nitroso compound is obtained bynitrosylation of a carbon acid having a pKa less than about 10. Whenused alone, this compound displays activity (NO donating and/orrelaxation activity) when used at micromolar concentrations and willnitrosylate the modestly nucleophilic thiol of a cysteine residue or alow molecular weight derivative (e.g., glutathione). The native activityis presumably mediated by nitrite derived from nitrosylation of water.This mode of action shows little if any specificity and is very weak. Asindicated above, it has been discovered in the course of this inventionthat this activity is potentiated by the presence of glutathione. Thispotentiation is roughly 1,000-fold.

We turn now to the subgenus where the C-nitroso compound is obtained bynitrosylation of a carbon acid having a pKa ranging from about 15 toabout 20. These C-nitrosothiols will not nitrosylate glutathione butwill selectively nitrosylate highly nucleophilic thiols found in proteintargets. Thus, highly nucleophilic thiols can be targeted by the use ofthese C-nitroso compounds.

The C-nitroso compounds described in “Methods in Nitric Oxide Research,”edited by Feelisch, M. and Stamler, J. S., John Wilen & Sons, New York(1996) are excluded from the invention herein.

The C-nitroso compounds described in Rehse, K, et al., Arch. Pharm.Pharm. Med. Chem. 331, 104-110 (1998) and Rehse, K, et al., Arch. Pharm.Pharm. Med. Chem., 331, 79-84 (1998) are excluded from theC-nitrosothiols of the invention.

Also excluded from the C-nitrosothiols of the invention are theC-nitrosodiones described in Sklyar, Yu. E., et al., KhimiyaGeterotsiklicheskikh Soedinenii 5,70-73 (1969).

The potentiation effect of glutathione on C-nitroso compounds derivedfrom carbon acids with pKa's less than 10 is new and is one embodimentof the invention herein.

The C-nitrosylated compounds herein, when isolated, form dimers whichare solid and very stable and therefore the compounds herein have longshelf lives and are capable of being stored at ambient temperatures inthe presence of oxygen and light for months. While the dimers areinactive, they form monomers in water which are active. They can beadministered as aqueous solutions for instant activity. They also can beadministered as dimers to provide sustained release effect as the dimerdissolves in the body. Thus, the dimers herein have been discovered topromote compound lifetime and modulate compound bioactivity, and therelease rates are not directly related to the activity of thesecompounds. The dimerization and greater stability are greatly favoredfor α-acyl C-nitroso compounds; hence the preference above for C-nitrosocompounds where carbon alpha to the nitrosylated carbon is part of aketone group.

As indicated above, C-nitroso compound herein is obtained bynitrosylating a tertiary carbon atom of a conventional drug or of aconventional drug modified to modify the carbon acid pKa thereof Thecarbon acid pKa can be reduced, for example, by converting a carbonalpha to tertiary carbon to be nitrosylated to a ketone group or by theaddition of other electron withdrawing substituent (e.g., fluorine,nitro or cyanide).

When C-nitroso compound is obtained from a conventional drug, it retainsthe functionality of the drug and also provides NO donating relaxingeffect. Sometimes this results in a synergistic effect. For example,when the C-nitroso compound is derived from a nonsteroidalanti-inflammatory drug which inhibits COX-1 as well as COX-2, the resultis a COX-1 inhibitor with the advantages but not the disadvantages ofCOX-1 inhibition by conventional NSAIDS and also a COX-2 inhibitor withthe advantages thereof and wherein certain beneficial effects (e.g.,amelioration of urinary incontinence or mediating preconditioning) maybe potentiated or newly endowed. A compound synthesized herein wasderived from ibuprofen which inhibits COX-1 as well as COX-2. In thesynthesis, the ibuprofen was first converted to ketoibuprofen to lowerthe pKa to be within 15 to 20. The nitrosylated compound, anitrosoketoibuprofen, isolated as dimeric2-[4′-(α-nitroso)isobutyrylphenyl]propionic acid, provides theadvantages of COX-1 and COX-2 inhibition without pathological effectstypically associated with COX-1 inhibition.

Below are listed conventional drugs and C-nitroso compounds of the firstembodiment of the invention derived therefrom

The analgesic acetylsalicylic acid has the formula

C-Nitroso compounds of the invention derived from acetylsalicylic acidinclude, for example:

In (1), (2) and (3), R₁, and R₂ are selected from the group consistingof C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives of these,e.g., substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The antianginal propanalol has the formula:

C-Nitroso compounds of the invention derived from propanalol include,for example:

In (4), (5) and (6), R₁, R₂ and R₃ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives ofthese, e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The antianginal nadolol has the formula:

C-Nitroso compounds of the invention derived from nadolol include, forexample:

In (7), (8) and (9), R₁, R₂, R₃, R₄ and R₅ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof, e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The antianginal and heart failure protective carvedilol has the formula:

C-Nitroso compounds of the invention derived from carvedilol include,for example:

In (10), R₁ and R₂ are selected from group consisting of C₁-C₆ alkyl andC₆-C₂₀ aryl and substituted derivatives thereof, e.g., substituted withamino, hydroxyl and/or carboxy and/or which are sulfated and/orphosphorylated.

The antihypertensive prazosin has the formula:

C-Nitroso compounds of the invention derived from prazosin which areexemplary of alpha adrenergic receptor agonists useful to treat erectiledysfunction, include, for example:

In (11), (12) and (13), R₁ and R₂ are selected from the group consistingof C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof,e.g., substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The antihypertensive tinolol has the formula:

C-Nitroso compounds of the invention derived from tinolol include, forexample:

In compounds (14), (15), (16), (17), (18) and (19), R₁ and R₂ areselected from the group consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl andsubstituted derivatives thereof e.g., substituted with amino, hydroxyand/or carboxy and/or which are sulfated and/or phosphorylated.

The antihypertensive metoprolol has the formula:

C-Nitroso compounds of the invention derived from metoprolol include,for example:

In compounds (20), (21), (22) and (23), R₁ and R₂ are selected from thegroup consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substitutedderivatives thereof e.g., substituted with amino, hydroxyl and/orcarboxy and/or which are sulfated and/or phosphorylated.

The antihypertensive pindalol has the formula:

C-Nitroso compounds of the invention derived from pindalol include, forexample:

Are (27) and (28) correct—note no N in ring?

In (24), (25), (26), (27) and (28), R₁ and R₂ are selected from thegroup consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substitutedderivatives thereof e.g., substituted with amino, hydroxyl and/orcarboxy and/or which are sulfated and/or phosphorylated.

The antihypertensive labetalol has the formula:

C-Nitroso compounds of the invention derived from labetalol include, forexample:

In (29), (30), (31) and (32), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The diuretic triamterene has the formula:

C-Nitroso compounds of the invention derived from triampterene include,for example:

In (33), R₁ and R₂ are selected from the group consisting of C₁-C₆ alkyland C₆-C₂₀ aryl and substituted derivatives thereof e.g., substitutedwith amino, hydroxyl and/or carboxy and/or which are sulfated and/orphosphorylated.

The diuretic furosemide has the formula:

C-Nitroso compounds of the invention derived from furosemide areuniquely useful in treating heart failure in combining diuretic andvasodilator functions and include, for example:

In (34), (35), (36) and (37), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof, e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The ACE inhibitor enalapril has the formula:

C-Nitroso compounds of the invention herein derived from enalapril haveimproved antianginal effect when used to lower blood pressure andimproved antiplatelet activity and include, for example:

In (38), (39), (40) and (41), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The ACE inhibitor rampiril has the formula:

C-Nitroso compounds of the invention herein derived from rampirilinclude, for example:

In (42), (43), (44) and (45), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof, e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The antihypercholesterolemic/antihyperlipoproteinemic lovastatin has theformula:

C-Nitroso compounds of the invention herein derived from lovastatininclude, for example:

In (46), (47), (48) and (49), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereon e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The antihypercholesterolemic/antihyperlipoproteinemic pravastatin hasthe formula:

C-Nitroso compounds of the invention herein derived from pravastatininclude, for example:

In (50), (51), (52), (53) and (54), R₁ and R₂ are selected from thegroup consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substitutedderivatives thereof e.g., substituted with amino, hydroxyl and/orcarboxy and/or which are sulfated and/or phosphorylated.

The antihypercholesterolemic/antihyperlipoproteinemic gemfibrozil hasthe formula:

C-Nitroso compounds of the invention herein derived from gemfibrozilinclude, for example:

In (55), (56), (57), (58), (59) and (60), R₁ and R₂ are selected fromthe group consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substitutedderivatives thereof, e.g., substituted with amino, hydroxyl and/orcarboxy and/or which are sulfated and/or phosphorylated.

The antihypercholesterolemic/antihyperlipoproteinemic clofibrate has theformula:

C-Nitroso compounds of the invention herein derived from clofibrateinclude, for example:

In (61 and (62), R₁ and R₂ are selected from the group consisting ofC₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof e.g.,substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The calcium channel blocker nifedipine has the formula:

C-Nitroso compounds derived from nifedipine include, for example:

In (63), (64) and (65), R₁ and R₂ are selected from the group consistingof C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof e.g.,substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The calcium channel blocker amlodipine has the formula:

C-Nitroso compounds of the invention herein derived from amlodipineinclude, for example:

In (66), (67), (68), (69) and (70), R₁ and R₂ are selected from thegroup consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substitutedderivatives thereof e.g., substituted with amino, hydroxyl and/orcarboxy and/or which are sulfated and/or phosphorylated.

The calcium channel blocker diltiazem has the formula:

C-Nitroso compounds of the invention herein derived from diltiazeminclude, for example:

In (71), (72), (73), (74), (75) and (76), R₁ and R₂ are selected fromthe group consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substitutedderivatives thereof, e.g., substituted with amino, hydroxyl and/orcarboxy and/or which are sulfated and/or phosphorylated.

The calcium channel blocker verapamil has the formula:

C-Nitroso compounds of the invention herein derived from verapamilinclude, for example:

where R is the same as in (77)

In (77), (78), (79), (80) and (81), R₁ and R₂ are selected from thegroup consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substitutedderivatives thereof e.g., substituted with amino, hydroxyl and/orcarboxy and/or which are sulfated and/or phosphorylated.

The antacid cimetidine has the formula:

C-Nitroso compounds of the invention herein derived from cimetidineinclude, for example:

In (82 and (83), R₁ and R₂ are selected from the group consisting ofC₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof e.g.,substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated,

The antacid ranitidine has the formula:

C-Nitroso compounds of the invention herein derived from ranitidineinclude, for example:

In (84) and (85), R₁ and R₂ are selected from the group consisting ofC₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof e.g.,substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The bronchodilator albuterol has the formula:

C-Nitroso compounds of the invention herein derived from albuterolinclude, for example:

In (86), (87) and (88), R₁ and R₂ are selected from the group consistingof C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof,e.g., substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The bronchodilator ipratropium bromide has the formula:

C-Nitroso compounds of the invention herein derived from ipratropiumbromide include, for example:

In (89), (90), (91), and (92), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof, e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The NMDA antagonist/skeletal muscle relaxant memantine has the formula:

C-Nitroso compounds of the invention herein derived from memantineinclude, for example:

where X is as in (95)

In (93), (94), (95), (96) and (97), R₁ and R₂ are selected from thegroup consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substitutedderivatives thereof e.g., substituted with amino, hydroxyl and/orcarboxy and/or which are sulfated and/or phosphorylated.

C-Nitroso derivatives of antiproliferative agents are especially used,as the NO group has antiproliferative effect and increases that of theagent before NO derivatization.

The antiproliferative/tubulin binding agent 10-deacetylbaccatin III hasthe formula:

C-Nitroso compounds of the invention herein that are derivatives of10-deacetyl-baccatin III include, for example:

In (98) and (99), R₁ and R₂ are selected from the group consisting ofC₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof e.g.,substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The antiproliferative/tubulin binding agent taxol has the formula:

C-Nitroso compounds of the invention herein derived from taxol include,for example:

In (100) and (101), R₁ and R₂ are selected from the group consisting ofC₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof, e.g.,substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The antitubercular PA-824 has the formula:

C-Nitroso compounds of the invention herein derived from PA-824 include,for example:

In (102) and (103), R₁ and R₂ are selected from the group consisting ofC₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof e.g.,substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The CETP inhibitor JTT-705 (Okamoto et al., Nature 406, 203 (2000)) hasthe formula:

C-Nitroso compounds of the invention herein derived from JTT-705include, for example:

In (104), (105), (106), (107) and (108), R₁ and R₂ are selected from thegroup consisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substitutedderivatives thereof, e.g., substituted with amino, hydroxyl and/orcarboxy and/or which are sulfated and/or phosphorylated.

C-Nitroso compounds derived from SOD mimetics include, for example:

where M is, for example, manganese, iron or cobalt, L is halide, nranges from 0 to 4 depending on the valence of M, and R is as in (109).

In (109) and (110), R₁ and R₂ are selected from the group consisting ofC₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivatives thereof e.g.,substituted with amino, hydroxyl and/or carboxy and/or which aresulfated and/or phosphorylated.

The xanthine oxidase inhibitor allopurinol has the formula:

C-Nitroso compounds derived from allopurinol include, for example:

In (111), (112), (113) and (114), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof, e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The COX-2 inhibitor Celebrex has the formula:

C-Nitroso compounds derived from Celebrex include, for example:

In (115), (116), (117) and (118), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The COX-2 inhibitor indomethacin has the formula:

C-Nitroso compounds derived from indomethacin include, for example:

In (119), (120) and (121), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof, e.g., substituted with ammo, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

The COX-2 inhibitor L-745,337 has the formula:

C-Nitroso compounds derived from L-745,337 include, for example:

and R₁ and R₂ are selected from the group consisting of C₁-C₆ alkylC₆-C₂₀ aryl and substituted derivatives thereof, e.g., amino, hydroxyland/or carboxy and/or which are sulfated and/or phosphorylated.

The COX-2 inhibitor etudolac has the formula:

C-Nitroso compounds derived from etudolac include, for example:

In (125), (126), (127) and (128), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl C₆-C₂₀ aryl and substituted derivativesthereof, e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated.

In all cases where R₁, R₂, R₃, R₄ or R₅ are defined above where H is notone of the named groups, R₁, R₂, R₃, R₄ and R₅ can also be H, providedthat the NO is attached to a tertiary carbon, i.e., so that defining R₁,R₂, R₃, R₄ and/or R₅ as H does not make NO attached to a carbon which isnot a tertiary carbon.

The compounds (1)-(128) are meant to be exemplary and as one skilled inthe art would understand, in many cases the chain on which the NO issubstituted can also be in a different location from the one depicted.

In many of the exemplified compounds, the nitric oxide bearing fragmentis linked through an ether or amino linkage. The ether linkage has theadvantage of stability in vivo. Alternatively, in some instances it canbe advantageous to link the NO-bearing fragment through an esterlinkage.

Examples of C-nitroso compounds of the invention herein where NO-bearingfragment is linked through an ester linkage are set forth below:

In (129), (130), (131) and (132), R₁ and R₂ are selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof e.g., substituted with amino, hydroxyl and/or carboxy and/orwhich are sulfated and/or phosphorylated, or can be H, provided thatdefining R₁ and R₂ as H does not make NO attached to a carbon which isnot a tertiary carbon. The compounds (129), (130), (131) and (132) aremeant to be exemplary, and knowing the above, one skilled in the art,could conceive of many other C-nitroso compounds of the invention hereinwhere NO-bearing fragment is linked through an ester linkage.

An example of a Compound (129) is:

An example of a Compound (130) is:

Both the compounds (129a) and (130a) are obtained by nitrosylation of acarbon atom having a pKa less than about 10.

We turn now to the synthesis of the C-nitroso compounds of the firstembodiment herein.

Several methods applicable to synthesizing C-nitroso compounds aredisclosed in Boyer, J. H., “Methods of Formation of the Nitroso Groupand its Reactions” in The Chemistry of the Nitro and Nitroso Groups,Part 1, Feuer, H., Editor, John Wiley & Sons, New York (1969) at pages215-299 and in Touster, O in Organic Reactions, Vol. 7, John Wiley &Sons, New York (1955) at pages 327-377 which are incorporated herein byreference.

In a method which is applicable to nitrosylation of carbon acids withpKa's less than about 15, the carbon acids can be directly nitrosylatedwith sodium nitrite and an acid such as glacial acetic acid after themethod of Sklyar, Yu. E., et al., Khimiya GeterotsiklicheskikhSoedinenii, 5, 70-73 (1969). This method is useful for preparing thesubgenus of compounds herein which are obtained by nitrosylation of acarbon acid having a pKa less than about 10.

In a method which is applicable to nitrosylating carbon acids with pKa'sbetween about 15 and 30, nitrosylation is carried out by formation ofthe enolate and trapping the enolate by a nitrosonium equivalent. Theenolate can be trapped directly or isolated as the silyl enol ether oran equivalent. This method is useful for preparing the subgenus ofcompounds herein obtained by nitrosylation of a carbon acid having a pKaranging from about 15 to about 20. It is the method used in Example Ihereinafter for preparing dimeric2-[4′-(α-nitroso)isobutyrylphenyl]propionic acid.

In a method useful for synthesizing C-nitroso compounds regardless ofthe acidity, the carbon acid is converted to the corresponding hydroxylamine which is oxidized, for example, using silver carbonate on Celite.

In the case of unstable C-nitroso compounds, it can be desirable tointroduce or unmask the C-nitroso fragment only in the final step of thesynthesis, or at least as late in the synthesis as possible. In one suchroute, the synthesis of the C-nitroso drug will first incorporate anappropriate fragment and nitrosylation is carried out only aftersynthesis is complete. An example this route is set forth below:

In the above reaction scheme, R₁ can be selected from the groupconsisting of C₁-C₆ alkyl and C₆-C₂₀ aryl and substituted derivativesthereof (as defined for R₁ and R₂ above), and X is chlorine or bromineand PPTS is pyridinium paratoluene sulfonic acid and “pyr” is pyridine.This route is especially suitable for the preparation of compoundsderived from parent carbon acids with especially low pKa values,typically less than 15 and preferably less than 10. For compoundsderived from parent carbon acids with higher pKa values, it ispreferable to carry the C-nitroso moiety masked as the bis-protectedhydroxylamine; the C-nitroso functionality is unmasked, for example,late in the synthesis, following attachment to a conventional drug, bymild oxidation with, for example, silver carbonate on Celite; an exampleof this mode of synthesis is set forth below:

In this reaction, LDA means lithium diisopropyl amide, TMSE meanstrimethylsilylethyl, R is TMSE, PG is a protecting group, and DCC isdicyclohexylcarbodiimide.

Derivatized compounds can be prepared utilizing as nitrosylating agent abromomethylketone derivative of either 3-nitroso-2,4-pentanedione or4-nitroso-2,3-butadione.

Substituted 3-nitroso-2,4-pentadiones can be prepared by the followingreaction scheme:

In the above reaction, scheme “PG” stands for protecting group and“pPTS” stands for pyridinium paratoluene sulfonic acid, R₁, R₂, R₃ andR₄ are the same or different and can be the same as R₁ is defined forreaction schemes above, and X is chlorine or bromine. The preparation isbriefly described as follows: A group is introduced by nucleophilicsubstitution at the most acidic position in standard fashion.Introduction of this group prevents formation of the oxime followingnitrosylation. The precise identity of the group is chosen to controlthe reactivity of the C-nitroso derivative. Electrophilic nitrosylationwith nitrosonium is followed by reduction to the hydroxylamine andprotection as the bisacyl derivative, as described in “Bis-protectedhydroxylamines as reagents in organic synthesis. A review:” in Romine,J. L., Org. Prep. Proced. Int. 28, 249-288 (1996). Differentiation ofthe dione by monoprotection as the ketal is followed by introduction ofone, two or three groups by nucleophilic substitution in the standardway. Deprotection of the ketal and the hydroxyl amine is followed bymild oxidation to the C-nitroso compound with, for example, silver (1)salts immobilized on Celite. Finally, conversion to the bromomethylketone with bromine and hydrobromic acid provides the derivatizingagent.

Substituted 4-nitroso-2,3-butadiones can be prepared according to thefollowing reaction scheme:

In the above reaction scheme, “pPTS” is pyridimium paratoluene sulfonicacid, “LDA” is diisopropyl amide and “PG” means protecting group R₁ andR₂ can be the same or different and can be the same as for the reactionschemes set forth above, and X is chlorine or bromine. The preparationis briefly described as follows: The dione of 2,3-butadione isdifferentiated as the monoketal and is then substituted by nucleophilicsubstitution in the standard fashion. Nitrosylation through the silylenol ether, followed by protection of the C-nitroso group as thediacylated hydroxylamine precedes deprotection of the ketal,regeneration of the C-nitroso functionality and bromination to thereactive α-bromoketone.

In the synthesis of compounds of the first embodiment herein, the carbonacid pKa of the starting material can be adjusted down by the provisiontherein of an electron withdrawing group and the carbon acid pKa can beadjusted up by the provision therein of an electron releasing group.

For example, an acidic center can be introduced, e.g., formation of aketone group from the carbon adjacent the carbon to be nitrosylated toincrease the acidity and provide lower carbon acid pKa startingmaterial. This approach was used in the synthesis of dimeric2-[4′-(α-nitroso)isobutyrylphenyl]propionic acid from ibuprofen setforth in Example I below. In the synthesis of Example I, ibuprofen(carbon acid pKa of approximately 50-55) was converted to2-(4′-isobutyrylphenyl)propionic acid (carbon acid pKa of about 20) bythis approach and the latter was converted to the final product by themethod of nitrosylating carbon acids with pKa's between about 15 and 30described above. The reaction scheme used in Example I to convertibuprofen to dimeric 2-[4′-(α-nitroso)isobutyrylphenyl]propionic acid isset forth below where 1A ibuprofen, 4A is2-(4′-isobutyrylphenyl)propionic acid and 6A is the dimeric product.

In the above reaction scheme, “TMSCl” stands for chlorotrimethylsilane.

In summary, there are fundamentally at least two different ways ofmaking compounds herein. One of these is to modify the parent drug tointroduce of the first embodiment herein functionality (ketone or dione)that allows C-nitrosylation. It is by this method that thenitrosoketoibuprofen is made herein. The other of these is to attach apiece or fragment to the drug that allows formation of —CNO. One methodof carrying out the latter is via a bromoketone to link via ether, amineor ester. Instead of using a bromoketone, a carboxylic acid derivativecan be reacted with hydroxy group or amine group of a conventional drugto obtain an amide or ester linkage.

The Compound (129a) can be prepared by the following route of synthesis:

The Compound (130a) can be prepared by the following route of synthesis:

We turn now to utility of the C-nitroso compounds of the firstembodiment herein.

The C-nitroso compounds of the first embodiment herein have utility asNO donors and in such function provide relaxation and plateletinhibiting effect. Thus, C-nitroso compounds of the first embodimentherein are useful to prevent restenosis following angioplasty inpatients at risk for restenosis following angioplasty and to inhibitplatelets to prevent coagulation and to treat angina in patients at riskfor coagulation and thrombus formation. The NO donor function alsoprovides the following therapeutic effects: inhibition of microbes andtreatment of impotence, asthma, heart failure, stroke, arthritis, ARDS,cancer and any pathological proliferation of cells and any NMDA relatedinjury.

As indicated above, the C-nitroso compounds of the first embodimentherein with high NO-donating capacity (from carbon acids with pKa's lessthan about 10) exhibit weak (micromolar concentration) effects, probablythrough nitrite and are potentiated by added glutathione or similar lowmolecular weight thiols. These compounds cause formation ofnitrosoglutathione and are therefore especially useful to treat patientsin need of nitrosoglutathione, e.g., patients with cystic fibrosis,asthma, hypoxia and ischemic disorders.

As indicated above, the C-nitroso compounds of the first embodimentherein with weak NO-donating capabilities (from carbon acids with pKa'sranging from about 15 to about 20) show high activities through specificnitrosylation of strongly nucleophilic targets and are therefore usefulto nitrosylate thiols in proteins in highly nucleophilic milieus andthus are useful to treat patients in need of nitrosylated proteins,e.g., patients with hypertension, neurodegeneration and painful crisisof sickle cell disease.

When C-nitroso compounds of the first embodiment herein are derived fromnonsteroidal anti-inflammatory drugs that inhibit COX-1 as well asCOX-2, the C-nitroso compounds are useful to treat inflammatory or paildisorders including arthritis, coronary artery disease and urinaryincontinence and improve the profile of selective inhibitors of COX-2,e.g., in the treatment of angina. The nitrosoketoibuprofen preparedherein has these utilities.

As indicated above and will be discussed in more depth in thedescription of advantages below, the stability of the dimeric form ofisolated C-nitroso compounds of the first embodiment herein improvescompound lifetime and provides modulated bioactivity. Thischaracteristic permits their use as sustained release drugs. Suchstability also connotes utility as prodrugs. Because spontaneous releaseof NO is both controllable and small many C-nitroso compounds will beactive only in the presence of small molecule activators, e.g.,low-molecular weight thiols acting as carriers of NO (in an appropriateredox form) from the C-nitroso compound to a biological target.

Moreover, C-nitroso compounds of the first embodiment herein can beincorporated into polymers for coatings on medical devices. In the caseof such coatings, polymerizable C-nitroso compounds can be copolymerizedwith appropriate monomers to yield plastics or elastomers as desired.

The polymers into which C-nitroso compounds of the first embodimentherein can be incorporated include all biocompatible polymers, includingPVP and PVP-urethane copolymers; hydrogels; polylactides andpolylactide-co-polyethyleneglycol; polyacrylonitriles,polyacrylonitrile/polyacrylamide/polyacrylic acid copolymers;polyurethanes, polycarbonates, polyethers and copolymers of the three;silicone polymers and copolymers; carbohydrate polymers, includingstarches and modified starches, cellulose and cellulosidic materials,chitin and chitosan, glycosamine glycans, including hyaluronic acid,chondroitin and chondroitin sulfate, wherein the polymer has beenmodified to incorporate C-nitroso moieties derived from carbon acidswith pKa values less than about 25. The C-nitroso moieties can be boundas esters or ethers to pendant hydroxyl groups, as esters to pendantcarboxylic acids or as amines or amides to pendant amino moieties. Thenitrosylated polymer itself can be prepared in a variety of ways.Nitrosylated monomers can be incorporated into a growing polymer duringeither a free radical, ionic, metathesis or living polymerization.Alternatively, a completed polymer can be derivatized followingsynthesis to incorporate the above listed residues by treating, forexample, hydroxylated or amine-containing polymers with carboxylic acidchlorides or alkyl halides, carboxylate-containing polymers with alkylhalides. Finally, a C-nitroso precursor, for example, a monomercontaining a dione or a vinyl silane can be polymerized into a growingpolymer chain by a free radical, ionic, metathesis or livingpolymerization and then nitrosylated following polymerization byexposure to a source of nitrosonium, for example acidified nitrite,titanium tetrachloride and an alkyl nitrite, respectively.

Said polymers, can have weight average molecular weights (determined bylight scattering) ranging, for example, from 50,000 to 500,000.

We turn now to dosages and methods of administration for the C-nitrosocompounds of the first embodiment herein when they are used fortherapeutic utility. using part of it as the C-nitroso derivative. Thereason for the wide range is that many compounds are embraced by theinvention.

Routes of administration include, for example, oral parenteral includingintravenous, inhaled, nebulized, and topical.

When the C-nitroso compound of the first embodiment herein is derivedfrom a conventional drug, the dosages utilized are those in use for theconventional drug and the methods of use are those for the conventionaldrug but, as indicated above, only part of the drug is administered asthe C-nitroso compound with the rest being admired as the conventionaldrug, if necessary.

When the C-nitroso compound is one obtained by nitrosylation of a carbonacid having a pKa less than about 10, it is preferably administered in aconcentration ranging from 1 nanomolar to 100 micromolar as an aqueoussolution unless potentiation is provided by glutathione or otherlow-molecular weight thiol whereupon the C-nitroso compound ispreferably administered in a concentration ranging from 1 to 900nanomolar and the glutathione is administered in a concentration rangingfrom 1 micromolar to 100 millimolar.

When the C-nitroso compound is one that is obtained from a carbon acidhaving a pKa ranging from about 15 to about 20, the C-nitroso compoundis preferably administered in a concentration ranging from about Inanomolar to 100 micromolar.

We turn now to the ibuprofen derivative, Le., dimeric2-[4′-(α-nitroso)isobutyrylphenyl]propionic acid. It is preferablyadministered as a pill, tablet or capsule or the like, wit only part ofthe ibuprofen being administered as the C-nitroso derivative, e.g., onepart by weight ibuprofen derivative, to 1,000 parts by weightunderivatized ibuprofen to provide 400 mg on an ibuprofen basis, threeto four times day and from 1 nanomolar to 100 micromolar C-nitrosocompound concentration.

The compounds of the first embodiment herein are advantageous over theC-nitroso compounds known heretofore in activity and/or in solubility.

We turn now to the advantages of the C-nitroso compounds of the firstembodiment herein over O-nitroso compounds and S-nitroso compounds as NOdonors.

A major barrier to use of organic nitrites and nitrosothiols as NO (Ornitrosonium) donors is their instability. For example, nitrosothiolsundergo rapid decomposition to yield inter alia nitric oxide radical anda sulfur radical In contrast, C-nitroso compounds of the firstembodiment undergo a dimerization reaction to produce a solid, stabledimer. As indicated above, this dimerization reaction proceedsspontaneously during isolation of C-nitroso compounds and thedimerization is greatly favored for u-acyl C-nitroso compounds. Ingeneral the dimers are solid and stable, capable of being stored atambient temperature in the presence of oxygen and light for months. TheC-nitroso compounds herein have a significant advantage over O-nitrosoand S-nitroso compounds of the first embodiment from the standpoint ofshelf stability.

The C-nitroso compounds of the first embodiment herein are alsoadvantageous over O-nitroso and S-nitroso compounds as NO donors in thattheir functionality, i.e., NO donating potential and reactivity, can betailored, while this is not the case for O-nitroso and S-nitrosocompounds.

We turn firstly to tailoring the NO donating potential of C-nitrosocompound of the first embodiment herein. This can be done in three ways.Firstly, the rate of transfer of nitrosonium equivalent is directlyproportional to acidity. Thus, NO donating potential is increased byobtaining C-nitroso compound from starting material with lower pKa.Secondly, the NO donating potential is related to the position(equilibrium constant) of the dimer-monomer equilibrium(thermodynamics). This property is because, as indicated above, thedimer is stable and inactive whereas the monomer is active. Thirdly, theNO donating potential is influenced by the rate of interconversion ofthe dimer and monomer (kinetics). This feature can be utilized, forexample, by positioning an acyl alpha to the nitroso carbon to slow downthe rate of interconversion to monomer. On the other hand, theNO-donating capability of organic nitrites and nitrosothiols is largelya function of the heteroatom (oxygen or sulfur); there is little in theway of relationship between structure and activity.

We turn now to tailoring of the reactivity of C-nitroso compounds. Thiscan be accomplished sterically or electronically. We turn now to thesteric tailoring of reactivity. The addition of steric bulk at theα-carbon slows transfer of a nitrosonium equivalent. Thus, for example,highly hindered protein sulphydryl receptors can be protected againstS-nitrosylation through use of highly hindered C-nitroso donors. We turnnow to electronic tailoring of reactivity. Firstly, the rate of transferof nitrosonium equivalent is directly proportional to the acidity of theparent carbon acid. Secondly, the reactivity can be tailored byselecting starting material with groups that can tailor donatingpotential. For example, addition of groups such as acyl andelectronegative substituents, will lower the acidity of the carbon acidand in turn enhance the NO⁺ donating capacity of the C-nitroso compound.Moreover, alteration of groups changes the form of nitric oxideliberated. The alteration of groups can change the acidity as much as10⁴⁰, greatly exceeding the range available with sulfur or oxygen-basedconjugates.

Methods for providing different groups in C-nitroso compound areavailable in the methods of synthesis described above wherebromomethylketone derivatives of either 3-nitroso-2,4-pentanedione on4-nitroso-2,3-butadione are used and these groups can influence themonomer-dimer properties and NO-donating potential of the final product.

We turn now to the C-nitroso compounds of the second embodiment herein.These contain the moiety

where X is S, O or NR where R is selected from the group consisting ofC₁-C₆ alkyl which is unsubstituted or which is substituted with one ormore alcohol, ether; ester or amide groups which contain from 2 to 10carbon atoms; and has a molecular weight ranging, for example, fromabout 100 to about 1,000.

A preferred subgenus of the second embodiment herein comprise thestructure:

where X is S, O or NR where R is as defined for the genus of the secondembodiment and n ranges from 0 to 4 and the corresponding protonatedcompounds (instead of existing with the negative charge).

The structure (135) may be substituted with C₁-C₆ alkyl or C₁-₆ alkylcarbonyl and includes the modification that the carbon pendant to X anda carbon within the parentheses can also be part of another ring. Forexample, a compound of the second embodiment herein is:

The compounds of the second embodiment form spontaneously fromcorresponding C-nitroso compounds that contain alcohol, thiol or amine.For example, the Compound (135a) is formed by the following route ofsynthesis:

where Bz stands for benzoyl.

The compounds of the second embodiment herein have utility as NO donorsas described above in conjunction with the C-nitroso compounds of thefirst embodiment and are used with the dosage ranges and routes ofadministration described in conjunction with the C-nitroso compounds ofthe first embodiment and are characterized by similar stability to thedimers of the C-nitroso compounds of the first embodiment.

We turn now to the embodiment herein directed to inhibitors of COX-2where a tertiary carbon on an oxygen or a sulfur is nitrosylated.

Examples of inhibitors of COX-2 where a tertiary carbon is nitrosylatedare compounds (115)-(128) set forth above.

Examples of inhibitors of COX-2 where an oxygen or sulfur isnitrosylated include, for example, derivatives of Celebrex,indomethacin, L-745,337, and etudolac.

Examples of compounds derived from Celebrex include the following:

Examples of compounds derived from indomethacin include the following:

An example of a compound derived from L-745,337 is

Examples of compounds derived from etudolac include the following:

In the compounds (200), (201), (202), (203), (204), (205) and (206), Yis S or O; R₁ and R₂ are H or C₁-C₆ alkyl; and X is C₁-C₆ alkyl, C₆-C₂₀aryl and substituted derivatives thereof e.g., substituted with amino,hydroxyl, and/or carboxy and/or which are sulfated and/orphosphorylated.

The COX-2 inhibitor compounds which are O-nitrosylated are obtained fromthe parent alcohol by treatment with an appropriate nitrosylating agent,e.g., acidified nitrite, nitrosyl chloride, nitrosyl bromide,nitrosonium perchlorate, nitrosonium hydrogen sulfate or nitrosoniumtetrafluoroborate.

The COX-2 inhibitor compounds which are S-nitrosylated are obtained fromthe parent thiol by treatment with an appropriate nitrosating agent,e.g., those set forth in the paragraph directly above or alkyl nitrite.

The dosage on a COX-2 inhibitor basis is the same as the dosage for theunderivatized COX-2 inhibitor. To effect this, only part of the COX-2inhibitor can be administered in the form of nitrosylated compound. Theroute of administration is the same as for the underivatized COX-2inhibitor.

The invention is illustrated by the following working examples.

EXAMPLE I Synthesis of Dimeric2-[4′-(α-Nitroso)isobutyrylphenyl]propionic Acid

The synthesis of dimeric 2-[4′-(α-nitroso)isobutyrylphenyl]propionicacid was carried out according to the reaction scheme for this set forthabove as follows:

To a solution of ibuprofen 1A (9.89 g, 48 mmol) in anhydrous EtOH (35mL) was added chlorotrimethylsilane (18.27 mL, 144 mmol) at roomtemperature, and the mixture was stirred at the same temperature for 2h. After the removal of the excess EtOH and chlorotrimethylsilane underreduced pressure, the oily residue was treated with ice-cold saturatedNaHCO₃ (150 mL), and the resulting mixture was extracted with hexanes(450 mL). The hexanes solution was washed with brine (3×50 mL), anddried over anhydrous Na₂SO₂. Evaporation of the solvent afforded ethyl2-(4′-isobutylphenyl)propionate 2A (11.24 g, in 100% yield) as acolorless oil.

Ester 2A (11.23 g, 48 mmol) was added dropwise to a stirred suspensionof CrO₃ (20.8 g, 208 mmol) in acetic acid (AcOH) (34 mL) and H₂O (1.1mL) within 30 min., maintaining the reaction temperature at 45-55° C.After the completion of addition, the mixture was stirred for 20 min,and then the mixture was heated with stirring at 50-55° C. foradditional 85 min, giving a blue-black suspension. The AcOH was removedunder reduced pressure, and the residue solid was suspended in ice-coldH₂O (400 mL), and extracted with EtOAc (450 mL). The extract was washedwith brine (5×50 mL), and dried (Na₂SO₄). The crude products werepurified by flash chromatography (eluting with 7% EtOAc in hexanes) togive unreacted ester 2A (2.78 g), followed by ethyl2-(4′-isobutyrylphenyl)propionate 3a (4.3 g, 48% yield based on consumed2A) as a light-yellow oil.

Fifteen percent aqueous NaOH (10 mL) was added to a solution of 3A (3.2g, 12.9 mmol) in MeOH (150 mL), and stirred at room temperature for 2 h.After the removal of the MeOH by evaporator, the dark-brown residue wastreated with ice-cold 2M HCl (100 mL), and the resulting grey-whitesuspension was extracted with EtOAc (400 mL), and finally dried(Na₂SO₄). Flash chromatographic purification of the crude products(eluting with 60% EtOAc in hexanes) afforded2-(4′-isobutyrylphenyl)propionic acid 4a (2.5 g, 88% yield) as anamorphous solid.

To a stirred mixture of 4A (1.59 g, 7.2 mmol) and triethylamine (3.03mL, 21.7 mmol) was added chlorotrimethylsilane (2.75 mL, 21.7 mmol) atroom temperature, and then a solution of sodium iodide (3.26 g, 21.7mmol) dissolved in anhydrous acetonitrile (25 mL) was introduced in oneportion. The mixture was stirred at room temperature for 8 h, thenextracted with hexanes (400 mL). The hexanes extract was washed withice-cold brine (2×30 mL), and dried (Na₂SO₄). Concentration of thesolvent afforded trimethylsilyl2-[4′-(1-trimethylsiloxy-1-isobutenyl)phenyl]propionate 5A (2.08 g, 79%yield) as a viscous oil, which was used without further purification.

A solution of 5A (2.1 g, 5.7 mmol) dissolved in anhydrous CH₂Cl₂ (25 mL)was cooled to −10° C. Isoamyl nitrite (2.4 mL, 17.6 mmol) was added inone portion, then 1M TiCl₄ CH₂Cl₂ solution (13.0 mL, 13.0 mmol) wasadded dropwise at −10° C. within a period of 20 min. After stirring atthe same temperature for additional 60 min, the resulting deep-greenmixture was poured into ice-cold H₂O (100 mL), and stirred for 5-10 min,then extracted with EtOAc (400 mL), and finally dried (Na₂SO₄).Evaporation of the solvent under reduced pressure gave an amorphoussolid, which was suspended in CH₂Cl₂ (50 mL) and collected byfiltration. The white solid was washed with additional CH₂Cl₂ (3×10 mL)to give dimeric 2-[4′-(α-nitroso)isobutyrylphenyl]propionic acid 6A(0.75 g, 53% yield).

EXAMPLE II

The ability of various C-nitroso compounds as described below to relax arabbit aortic ring (smooth muscle) was carried out as described inStamler, J., et al, PNAS, Vol. 89, 444-448 (1992).

Results shown in FIGS. 1-10 which are tracings of force (tension) in theY-direction versus time in the X-direction with downward directionindicating relaxation and upward direction indicating constriction.Concentrations of C-nitroso compound applied at time in the X-directionare indicated as 10⁻⁹ (1 nanomolar), 10⁻⁶ (1 micromolar), 10⁻³ (1milimolar), etc. “PE” on the figures means the application ofphenylephrine, a constricting agent.

FIG. 1 shows results for Compound (129a) which is a C-nitroso compoundobtained by nitrosylating a carbon acid with a pH less than 10.Relaxation effect is shown in FIG. 1 at 10 μM concentration, i.e., atmicromolar concentrations.

FIG. 2 shows results for C-nitroso-methylmalonic acid. It is obtainedfrom a carbon acid with a pKa of about 30-3 5. As shown in FIG. 2, itdisplays relaxation effect at 10 micromolar concentration (very weakactivity).

FIG. 3 shows results for C-nitrosobenzene. It is obtained from a carbonacid having a pKa of about 45. As shown in FIG. 3, it displays noactivity at micromolar concentration.

FIG. 4 shows results for C-nitrosophenol. C-Nitrosophenol is obtainedfrom a carbon acid having a pKa greater than 25. As shown in FIG. 4, itdisplays no activity at micromolar concentrations.

FIG. 5 shows results for the nitrosoketoibuprofen synthesized in ExampleI. As shown in FIG. 5, it displays relaxation effect at 10 nanomolarconcentration.

FIG. 6 shows further results for the nitrosoketoibuprofen synthesized inExample I. FIG. 6 shows the same relaxation effect at 10 nanomolar asdoes FIG. 7 but not much more activity at higher concentration (sincethe equilibrium moves in the direction of inactive dimer at higherconcentrations).

FIG. 7 shows results for the nitrosoketoibuprofen synthesized in ExampleI used in conjunction with 100 μM glutathione. As shown in FIG. 7, thereis no activity because glutathione blocks the activity of thenitrosoketoibuprofen by complexing with it to tie up the NO group (thesame occurrence as for dimer); this is a reflection of the C-N(O)R groupdescribed above.

FIG. 8 shows more results for the nitrosoketoibuprofen synthesized inExample I. Relaxation is shown at 1 and 10 nM concentration. Thisdiffers some from what is shown in FIGS. 5 and 6 because of the naturalvariability among blood vessels.

FIG. 9 shows results for 3-methyl-3-nitroso-2,4-petanedione which isobtained from a carbon acid with a pKa less than 10. This compound isnot water soluble. It displays relaxation effect at concentrationgreater than 10 micromolar and further effect at concentration greaterthan 100 micromolar, but when 100 μM glutathione is added it displaysrelaxation effect at between 1 and 10 nanomolar concentration. Thepotentiation effect occurs because the C-nitrosodione reacts withglutathione to form S-nitrosoglutathione.

FIG. 10 shows results for 2-methyl-2-nitrosopropane. It is obtained froma carbon acid having a pKa of about 55 and is not water soluble. Itdisplays no relaxation effect activity at any the concentrations used.

EXAMPLE III

A 60-year-old white male with arthritis, esophageal spasm, coronaryartery disease, congestive heart failure, impotence and nightly urinaryincontinence develops gastrointestinal upset when administered ibuprofen(400 mg, three times a day). When the drug is changed so that 0.1% byweight of the drug is administered as the dimeric nitrosoketoibuprofenof Example I, all symptoms are relieved.

EXAMPLE IV

A 65-year-old male with angina treated with nitroglycerin developsnitrate tolerance. Nitroglycerin administration is stopped and Compound(135a) is given at 20 μg/min continuously with relief of angina.

EXAMPLE V

A 62-year-old white male with severe rheumatoid arthritis presents withmyocardial infarction. His nonsteroidal anti-inflammatory drug isstopped because of concerns of increased cardiovascular risk. His jointpain becomes debilitating. Celebrex is administered orally twice a dayin 200 mg amount except that 0.1% by weight of the drug is administeredas Compound (115) where R₁ and R₂ are methyl, with relief of both jointpain and angina.

When Compound (200) where R₁ and R₂ are H and X is —CH₂—, and Y is S orO is substituted for the Compound (115) in equal amount, relief of bothjoint pain and angina is also obtained.

Variations

Variations of the above will be obvious to those skilled in the art.Thus, the scope of the invention is defined by the claims.

1-24. (canceled)
 25. A compound consisting of H⁺ with a counterionhaving the structure:

where X is S, O or NR where R is selected from the group consisting ofC₁-C₆ alkyl which is unsubstituted or which is substituted with one ormore alcohol, ether, ester or amide groups which contain from 2 to 10carbon atoms and n ranges from 0 to 4, where the carbon pendant to X anda carbon within the parentheses are part of another ring and where thestructure may be substituted with C₁-C₆ alkyl or C₁-C₆ alkyl carbonyl.26. (canceled)
 27. The compound according to claim 25 where X is O. 28.The compound according to claim 25 where the counterion has thestructure: